The present embodiments relate to computers and computer networks, and are more particularly directed to an interconnection of an Ethernet network to a 1394 network.
Data communication is now a key part of modern computing, and is available over a wide variety of networks. This data communication may be used for various reasons, such as business, science, personal, or purely entertainment. The various media to communicate data between users also has proliferated. Such media include both local area networks (LANs) as well as wide area networks (WANs). There is likely no clear formal line between the definition of a LAN or a WAN, but it is generally accepted that a LAN is for more local communication of data such as within a small location, building, or complex, while a WAN is for communication of data across a greater distance which may be across a nation or even worldwide. In any event, the existence of networks for purposes of data communication is now very popular, and appears to be a way of life for the foreseeable future.
Given the acceptance and proliferation of data communication among networks, over the past several years various types of networks have evolved to allow internetwork communication, that is, communication between host computers connected to two or more independent networks. Often these networks are heterogeneous architectures, meaning that at the network level one network has various attributes differing from the other network. Therefore, various governing groups and organizations have created standard techniques to allow communication between host computers on different network types, where that communication at the host level often appears to form a homogeneous network. These communication techniques are known as protocols, and are often implemented within each host rather than in the network medium. Moreover, such protocols are often located in an ordered manner such that the protocol handling occurs between the host's application level and the host's physical connection to its respective network. In any event, the protocol effectively hides the details of network hardware from the user and allows computers on different network types to communicate with one another independent of the network types.
One considerably prolific network protocol is known in the art as TCP/IP, where this name is actually a combination of the two standards used in the protocol. The first protocol is TCP which is an abbreviation for transport control protocol. The second protocol is IP which is an abbreviation for internetwork protocol. Although the name TCP/IP combines these two standards, in actuality the standards are implemented in an ordered level manner such that the TCP protocol is closer to the application level and the IP protocol is closer to the physical network connection level. Further, TCP/IP is well known and permits packets of information to be sent and received along different types of networks. For detailed information on TCP/IP, the reader may find numerous contemporary and commercially available publications, such as “Internetwork With TCP/IP,” Volumes I through III, by Douglas E. Comer, Third Edition (1995 by Prentice Hall), which is hereby incorporated herein by reference.
By way of further background, one technique for permitting internetwork communication using P involves the use of so-called routers. A router is a computer which is physically connected to two different networks, and which may receive an information packet from a source host computer on one network and communicate it to a destination host computer on the other network. Note, however, that the use of a router also involves various complexities. This process is performed using subnetting as is known in the art. For example, to use the functionality of the router, each host computer on each network is particularly configured at the IP level to communicate with the IP level of the router when internetwork communication is desired. In other words, if a host computer intends to communicate an internetwork information packet to a destination host computer, then the host computer forms the information packet to include the IP information of the destination host computer and further encapsulates this information with the IP information of the router. Next, when the router receives the encapsulated packet, it recognizes from the multiple levels of IP information that the packet is ultimately intended for a destination host computer on another network. Thus, the router is required to take still additional action at the IP level. For example, the router strips the outer IP information from the packet, thereby leaving the IP information pertaining to the destination host computer. Note, however, that this stripping action changes the checksum or other appropriate verification information included with the information packet. Thus, the router is further required to re-calculate the checksum and include the new value with the packet prior to sending that packet on to the destination host computer. In addition to these complexities, note also that because the router functionality is at the IP level of communication, then it is typically required that it be included with an operating system for that computer to perform the above-discussed functionality. Some operating systems, however, do not include such functionality. Thus, either a more complex and often more expensive operating system is required to provide the router functionality, or the software provider is required to re-write the operating system to extend the IP to further include the router functionality. One skilled in the art will therefore appreciate these as well as various other complexities arising from internetwork communications performed by routers.
In view of the above, as more network types are created and grow in popularity, there arises a need to permit such networds to internework with already-existing networks. The present embodiments are directed at such a need, and arise specifically in the context of Ethernet and 1394 networks as detailed below.